Manipulation of plants to alter and/or improve phenotypic characteristics (such as productivity, quality or pest resistance) requires the expression of heterologous genes in plant tissues. Such genetic manipulation relies on the availability of a means to drive and to control gene expression as required. For example, genetic manipulation relies on the availability and use of suitable promoters which are effective in plants and which regulate gene expression so as to give the desired effect(s) in the transgenic plant. For numerous applications in plant biotechnology a tissue-specific expression profile is advantageous, since beneficial effects of expression in one tissue may have disadvantages in others. For example, promoters driving expression in the plant epidermis, such as epidermis-preferential or epidermis-specific promoters are useful for expressing genes that prevent pathogens such as fungi or bacteria from infecting a plant through the epidermis. It is advantageous to have the choice of a variety of different promoters so that the most suitable promoter may be selected for a particular gene, construct, cell, tissue, plant or environment. Moreover, the increasing interest in transforming plants with multiple plant transcription units (PTU) and the potential problems associated with using common regulatory molecules for these purposes merit having a variety of promoter molecules available.
There is, therefore, a constant need in the art for the identification of novel molecules that can be used for expression of selected transgenes in economically important plants. It is thus an objective of the present invention to provide new and alternative expression cassettes for expression of transgenes in various tissues of plants, for example in the epidermis. The objective is solved by the present invention.